DERBY — Starting this summer, Griffin Hospital’s vending machines, which carry everything from soft drinks to bottled water to sandwiches and ice cream, are displaying NuVal scores for each vended item. The NuVal Nutritional Scoring System ranks all foods on a scale of 1 to 100. The higher the score, the higher the foods’ overall nutrition. Griffin Hospital helped create NuVal in 2008 with David Katz, MD, director of the Yale-Griffin Prevention Research Center.